Spray gun for applying heavy asphalt mastic



April 27, 1954 R. E. KELLEY 2,676,847

SPRAY GUN FOR'APPLYING HEAVY ASPHALT MASTIC Filed April 11, 1951Patented Apr. 27, 1954 SPRAY GUN FOR APPLYING HEAVY ASPHALT MASTICRaymond E. Kelley, Snyder, N. Y.

Application April 11, 1951, Serial No. 220,373

1 Claim.

This invention relates to pressure spray guns and is particularlyconcerned with such guns which are designed and intended for use inspraying thick viscous materials such as heavy asphalt mastic.

It has heretofore been common practice to provide thin coatings ofliquids of various compositions and characteristics on surfaces by theuse of spray guns and a number of different pressure guns have beendevised for and used in the application of such sprayed coatings. Therehas, however, existed a need for a pressure gun which is adapted for usein applying thick spray coatings of heavy viscous liquids such, forexample, as heavy asphalt mastic. This material is a mixture of thick,heavy asphalt with a considerable amount of insoluble filler such asasbestos fiber and is used extensively in waterproofing or damp-proofingconcrete and masonry structures, for which purpose it is applied incomparatively thick coats in some cases up to inch in thickness. Becauseof the large amount of filler and the inherent viscosity of the asphalt,the application of such mastic to surfaces which are to be water-proofedhas heretofore required hand application with a trowel or similar tool.Spraying has not been feasible with pressure guns of previous designssince in such guns the mastic is not sufiiciently broken up and istherefore deposited as large lumps or gobs instead of as a fine spraywhich enters and properly seals the pores in the surface being coatedand provides a coating of uniform thickness.

By the present invention there is provided a pressure spray gun which isso designed that even with air supplied at pressures of the ordercommonly employed viscous materials such as heavy asphalt mastic will bebroken up and emitted from the gun as a fine spray instead of beingemitted in gobs.

Another object is to provide such a gun which will produce a coating ofuniform thickness following the contour of even extremely roughsurfaces, the coatingbeing as thick on the sides of deep cavities as itis against the bottoms of these cavities or the exposed surfacessurrounding these cavities.

The invention further comprehends the provision of a pressure spray gunof the type described which is of simple, inexpensive construction,which is" easily adjusted, and which may easily be taken apart forcleaning when necessary.

The construction and further advantages of the pressure gun of thepresent invention will be more fully understood from. the followingdescription taken in conjunction with the accompanying drawings inwhich:

Fig. 1' is a longitudinal sectional view of a pressure spray gunconstructed in accordance with the present invention;

Fig. 2 is a longitudinal sectional view of the pressure gun illustratedin Fig. 1, the view being taken on line 2-2 of Fig. 1, but with theliquid inlet nipple and delivery tube being shown in plan;

Fig. 3 is a transverse sectional view taken on the line 3-3 of Fig. 1;and

Fig. 4 is a transverse sectional view taken on the line d@ of Fig. 1.

As illustrated, the pressure spray gun of the present inventioncomprises a body II which is essentially a lateral fitting having acylindrical through passage I2 and a cylindrical lateral passage I3communicating at one end with the through passage I2 and extending tothe exterior of the body I I through an integra1 boss it. The left endof the passage i2, as viewed in Fig. 1, is provided with screw threadsIt in which there is threadedly engaged one end I7 of a degree elbowfitting I8. The other end it of the fitting i8 is provided with interiorthreads and has secured therein by said threads a liquid inlet pipe 20.

The end I i of the elbow fitting I8 has mounted therein as by threads iian elongated liquid de-= livery tube 22 which is arranged concentricallywithin the cylindrical passage I2 and extends outwardly through theright end of the body H. A fitting such as a nipple 24 is threadedlyengaged in the outer end of the boss I4 and has connected thereto, bysuitable means such as threads, an air inlet pipe 25.

The cylindrical through passage I2 in the body it is provided at itsright end, as viewed in Fig. 1, with screw threads 26 in which there isengaged one end of an externally threaded, tubular mixing shell 27. Theshell 21 extends outwardly from the body H and is provided with acylindrical bore 28 into which the outer end of i the liquid deliverytube 22 extends in concentric arrangement with the open, outer end 29 ofthe tube 22 being adjacent the frusto-conical end Wall 39 of the shell.An axial outlet 32 is pro vided through the end wall 3%} and aplurality, preferably at least four, equally spaced auxiliary outlets 33of smaller diameter than the outlet 32 are provided in the conical faceof said wall in a circle concentric with the axial outlet. The shell 27may be axially adjusted by turning it in or out of the body I I to varythe distance of the end wall 3i! from the tube end 29 and thereby tovary the flow of air andliquid through the auxiliary ports or outlets33.

A nozzle 34 having an internally threaded bore 36 .is threadedly engagedon the outside of the mixing shell 21. At its inner end the bore 36 isreduced in diameter, the walls of the bore being internally bevelled atsubstantially the same angle as that of the frusto-conical end wall 3i!of the mixing shell 21. An axial outlet passage 31, which is elongatedso that its length is substantially greater than its diameter, providescommunication between the inner end of the bore 36 and the inner face ofa depression 33 formed in the outer end of the nozzle 34.

It will be seen that the construction hereinabove described provides apressure spray gun in which mixing of air with the viscous liquidmaterial being sprayed takes place in two separate mixing chambers. Thefirst mixing chamber is in the end of the bore 28 of the mixing shell 27between the open end 29 of the liquid delivery tube 22 and the end wall3%, while the second mixing takes place within the nozzle 35 at theinner end of the bore 36.

In using the improved pressure gun of the present invention the viscousliquid, such as heavy asphalt mastic, is supplied through the inlet pipe2@ and flows through the elbow fitting i8 and the elongated liquiddelivery tube 22. The viscous liquid may be fed to the gun by anysuitable means such as a pump, air pressure or gra vity. At the sametime air under pressure is admitted to the pressure gun through the pipe25. The compressed air flows through the passage it into the passage l2of the body ii and then through the annular space between the deliverytube 22 and the mixing shell 21 to the end of the bore 28 of the shell.

Since the mixing shell 27 is threadedly engaged in the body ii, it isaxially adjustable with respect to the liquid delivery tube 22 and thefrusto-conical end wall 30 is preferably so positioned with respect tothe end 29 of the tube that some air is mixed with the viscous liquidwhich passes from the tube 22 into the first mixing chamber provided inthe shell 27 and through the extension of said mixing chamber constituted by the axial outlet 32 of the shell, while the remaining portionof the air passes from the annular space around the tube through theauxiliary outlets 33 into the bore 36 of the nozzle 3% where it mixeswith the viscous liquid whi h has entered the bore 36 through the axialoutlet 32. Thorough mixing of the air and liquid takes place in thesecond mixing chamber and the aerated mixture is forced through theelongated outlet passage 3.1, emerging at the outer end of the passageas a spray in which the viscous li uid is in finely divided form whichmay be deposited on surfaces to give an even, smooth coat.

The concavity or depression 38 in the outer end of the nozzle 34 has atendency to confine the spray and form. it into a cylindrical stream inwhich spattering is minimized and thereby facilitates accuratedepositing of the spray material. Locknuts ll and d2 threadedly engageon the outside of the tubular mixing shell 2! and, respectively, securethe shell in adjusted position with respect to the liquid delivery tube22, and the nozzle 34 in adjusted position with respect to the end wall30 of the mixing shell 21.

By the practice of the present invention, the heavy asphalt mastic isapplied as a coating of uniform thickness on surfaces which areextremely irregular as well as smooth surfaces, which coating of uniformthickness closely follows the contour of irregular surfaces includingthe sides of deep and irregular depressions as well as the bottoms andrims thereof. With present spray guns, when used with heavy masticonirregular surfaces, 2. heavy deposit is made on the bottoms of deepdepressions as well as on the surface from which the depression extendsbut little, if any, of the heavy mastic is deposited on the sides of thedepression. This condition is corrected with the use of the gunembodying the present invention.

It will be evident that the pressure spray gun of the present inventionprovides for the spraying of viscous liquids such as heavy asphaltmastic and similar materials in a highly satisfactory and efficientmanner. It will also be seen that the construction .of the pressure gunis simple and that it may be readily adjusted in accordance with factorssuch as the temperature, viscosity and pressure of the fluids to provideproper mixing thereof and a uniform spray of finely divided liquidparticles;

it will be understood that numerous modifications and variations in theconstruction of the pressure gun herein described may be made asoccasion arises without departing from the spirit of the invention. Itis, therefore, intended that the invention shall not be consideredlimited to the specific embodiment shown in the drawings and describedherein, but that it shall be inter-- preted broadly and restricted onlyas may be re quired by the scope of the appended claim.

I claim:

A pressure gun for spraying heavy asphalt mastic comprising a bodyhaving a through passage and a lateral passage, said body at one e d ofthrough passage being provided w means for attaching an inlet pipethereto, s lateral passage communicating at its inner e with saidthrough passage and said body at outer end of said lateral passage beingprovided with means for attaching an inlet pipe thereto, a tubularmixing shell secured to said body at the other end of said throughpassage and extending outwardly from said body, said shell co1nprising abore communicating with said through passage and having, at its cuterend, a first ing chamber, a frusto-conical end wall provide with anaxial outlet from said mixing cham a plurality of auxiliary outletsspaced l'ur dially from said axial outlet, a mastic delivery tubemounted in said body and communicating at one end with the inlet to saidthrough pas-- sage, said tube projecting outwardly from said body intothe bore of said shell and having other .end spaced from said outletsfrom 1 bore, said shell being axially adjustable with r spect to saidtube, and a tubular nozzle moui on said shell and axially adjustablethereon, nozzle having a second mixing chamber and an outlet passageproviding communication between said chamber and the outer end of saidnozzle.

References Cited in the file of this patent 174,904 France Mar. 26, 1915

